Mimosa pudicaL. is a creeping annual or perennial herb. It has been identified as Lajjalu in Ayurveda and has
been found to have antiasthmatic, aphrodisiac,
analgesic and antidepressant. In the present study the active phytocomponents of Mimosa
pudicawere
revealed using phytochemical analysis. The
antimicrobial activity of Mimosa
was studied using well diffusion method. The activity was tested against Aspergillusfumigatus, Citrobacterdivergens and Klebsiella pneumonia at different concentrations
of 50, 100 and 200µg/disc and the results have been illustrated.

Herbal medicine involves the use of
plants for medicinal purposes. The term “Herb” includes leaves, stems,
flowers, fruits, seeds, roots, rhizomes and bark. There can be little doubt
that the use of plants for healing purposes is the most ancient form of
medicine known. The quest for plants with medicinal properties continues to
receive attention as scientists are in need of plants, particularly of ethno
botanical significance for a complete range of biological activities, which
ranges from antibiotic to anticancerous. Several
plants and herb species used traditionally have potential antimicrobial and
antiviral properties (Shelef, 1983; Zaika, 1988) and this has raised the optimism of scientists about the
future of phyto-antimicrobial agents.(Daset al.,1999).

Several
phytochemical surveys have been published,
including the random sampling approach which involved some plant accessions
collected from all parts of the world. The major chemical substances of
interest in these surveys were the alkaloids and steroidal sapogenins, however other diverse groups of naturally
occurring phytocomponents such as flavonoids, tannins, unsaturated sterols, triterpenoids, essential oils etc., have also been
reported (Lozoyaet al., 1990). There is currently a large and ever expanding
global population base that prefers the use of natural products in treating
and preventing medical problems because herbal plants have proved to have a
rich resource of medicinal properties.

Mimosa pudica L. is a creeping annual or
perennial herb often grown for its curiosity value, as the compound leaves
fold inward and droop when touched and reopens within minutes. It belongs to
the Fabaceae family. Mimosa pudicais native to Brazil,
but is now a pan tropical weed. The other names given to this plant are Humble
plant, Shame plant, Touch me not (Germplasm
Resources Information Network, 2008), Sleeping grass (Tropical Biological
Association), Prayer plant, The species epithet “pudica”
is a latin equivalent for “Bashful” or “Shrinking”,
because of its curious nature and easy procreation. The stem is erect in
young plants, but becomes creeping or trailing with age. The plant grows to a
height of 1.5m (5 ft). The leaves are bipinnately
compound, with one or two pinnae pairs and 10-26
leaflets per pinna. The petioles are also prickly
and on close examination, it is seen that the floret petals are red in their
upper part and the filaments are pink to lavender. The fruit consists of
clusters of 2-8 pods of 1-2cm long each, prickly on the margins. The pods
break into 2-5 segments and contain pale brown seeds 2.5mm long (US Forest
Service, 2008)

This plant has a history of use for the
treatment of various ailments and the most commonly used plant part for this
purpose is the root, but flowers, bark and fruit can
also be utilized. Several research works have been carried out to study about
the phytochemical components of Mimosa pudica
(Ahmad and Beg, 2001; Arthur, 1954; Deininger,
1984) and also about the antimicrobial activity of the plant (Palacios. et al., 1991; Ojalaa,
et al., 1999). The present study
intends to study about the antibacterial Activity of the Plant Extracts of Mimosa pudicaagainst
selected Microbes.

Materials and Methods

Sample Preparation

Mimosa pudica leaves were collected
together and shade dried. Since certain compounds get denatured in sunlight,
it is dried under shade to avoid decomposition. The dried leaves were then
pulverized well in an Udy cyclone mill. About 20g
of the powdered leaves were soaked in 100ml of methanol. It was left for 24
hours so that alkaloids, terpenoids and other
constituents if present get dissolved. The methanolic
extract was filtered using Whatmann 41 filter
paper. It was again filtered through Sodium sulphate
in order to remove the traces of moisture.

Preliminary Phytochemical
Screening

Phytochemical
screening of the plant extract was carried out as per the methods and tests
given by Dey and Raman (1957) to decipher the
presence or absence of various phytocompounds.

Antimicrobial Assay

Media Preparation

Bacterial Media (Muller Hinton Media)

36g of Muller Hinton
Media (Hi-Media) was mixed with distilled water and then sterilized in
autoclave at 15lb pressure for 15 minutes. The sterilized media were poured
into petri dishes. The solidified plates were bored
with 5mm diameter cork bearer. The plates with wells were used for the
antibacterial studies.

Fungal Media (Potato dextrose sugar)

200g of potato slices were boiled with
distilled water. The potato infusion was used as water source of media
preparation. 20g of dextrose was mixed with potato infusion. 20g of agar was
added as a solidifying agent. These constituents were mixed and autoclaved.
The solidified plates were bored with 6mm diameter cork borer. The plates
with wells were used for antifungal studies.

Antibacterial activity of the plant
extract

The methanolic
extract of 50µg, 100µg and 200µg were tested against two bacterial pathogens
namely Citrobacterdivergens
and Klebsiellapnemoniae,
for their antimicrobial activity. It was demonstrated by well diffusion method.

Antifungal activity of the plant
extract

The methanolic
extract and aqueous extract of 100, 200 and 500µg were tested against
different fungal pathogen Aspergillusfumigatus for their antifungal activity. It was
demonstrated by well diffusion assay.

Well diffusion method

Antibacterial and Antifungal activities
of the plant extract were tested using Well diffusion method (Bauer et al ., 1996). The prepared culture
plates were inoculated with different selected strains of bacteria and fungi
using streak plate method. Wells were made on the agar surface with 6mm cork
borer. The extracts were poured into the well using sterile syringe. The
plates were incubated at 37ºC+2ºC for 24 hours for bacterial and 25+2ºC
for 48 hours for fungal activity. The plates were observed for the zone
clearance around the wells.

The extract of the dried leaves was
used for the study. The methanol extract was dissolved in sterile distilled
water to form dilution such as 50µg, 100µg and 200µg. Each concentration of
the plant extract was tested against different bacterial pathogens. It was
demonstrated by well diffusion assay (Bauer et al .,
1996). The zone of inhibition was calculated by measuring the diameter of the
inhibition zone around the well (in mm) including the well diameter. The
readings were taken in three different fixed directions in all 3 replicates
and the average values were tabulated.

Results

The preliminary Phytochemical
screening of Mimosa pudica
extract showed the presence of bioactive components like Terpenoids,
Flavonoids, Glycosides, Alkaloids, Quinines,
Phenols, Tannins, Saponins and Coumarin
(Table 1).The results of the antimicrobial assay of the methanolic
extract of Mimosa pudica
indicated that the plant exhibited antimicrobial activity against the tested
microorganisms at three different concentrations of 50, 100 and 200µg/disc.
The potential sensitivity of the extract was obtained against all the three
micro organisms tested and the zone of inhibition was recorded and presented
below in the tabulation drawn (Table 2).

In the present era, plant and herb
resources are abundant, but these resources are dwindling fast due to the
onward march of civilization (Vogel, 1991). Although a significant number of
studies have been used to obtain purified plant chemical, very few screening programmes have been initiated on crude plant materials.
It has also been widely observed and accepted that the medicinal value of
plants lies in the bioactive phytocomponents
present in the plants (Veeramuthuet al., 2008). In the present
investigation, the active phytocomponents of Mimosa pudica
was studied and further the antimicrobial activity of the plant extract was
also tested against three potentially pathogenic microorganismsAspergillusfumifatus, Citrobacterdiversens and Klebsiella pneumonia
at different concentrationsof the extract to understand the most effective activity. The
maximum zone of inhibition was obtained for Aspergillusfumigatus and Klebsiella pneumonia at a concentration of 200µg/200µl. While Klebsiella pneumonia exhibited good sensitivity
against both the concentrations, Citrobacterdivergensshowed resistance against Mimosa pudica
extract at all concentrations.

From the above studies, it is concluded
that the traditionalplants may represent new sources ofanti-microbials
with stable,biologically active components
that can establish a scientificbase for the use of
plants in modern medicine. These local ethnomedicalpreparations and prescriptions ofplant sources should be
scientificallyevaluated and then disseminated properly and the
knowledge about the botanical preparation oftraditional sources of
medicinal plants can be extended for future investigation into the fieldof pharmacology, phytochemistry,
ethnobotany and other biologicalactions
for drug discovery.